Known stretch sheet materials with wrinkles or creases include those composed of a stretch sheet and a nonstretch sheet discretely bonded to each other and having wrinkles formed of the non-bonded regions of the nonstretch sheet by the retraction or contraction of the stretch sheet (see Patent Document 1 and Patent Document 2).
There has been proposed an elastic composite material composed of an elastic sheet in its relaxed state and a base sheet in its non-extended state or in a state forming no wrinkles or creases, in which the elastic sheet is bonded to the base sheet continuously in the longitudinal direction (MD) and discontinuously in the transverse direction (CD), and the base sheet has extensibility with no retractability in the CD (see Patent Document 3).
These conventional stretch sheet materials are liable to fail to have visually attractive ridges (creases) on account of irregularity of the shape of the creases or poor shape retention of the creases. In addition, production of the conventional stretch sheet materials involves discrete bonding a stretch sheet and a nonstretch sheet, which incurs the cost of equipment or a system.
Patent Document 1EP0591647A2Patent Document 2US2002156444A1Patent Document 3JP 5-222601A